There are many applications in which the detection of a sinusoidal signal is required. For example, in a multipoint data network, the beginning of a transmission by one station on the network may be indicated by a timing signal formed by one or more sinusoidal signals. Such a timing signal is recognized by receivers on the network as an indication that a packet of data will follow on the network. Accurate and rapid detection of a sinusoidal signal is critical in such an application. However, this is merely one example of the use of a sinusoidal signal detector.
Other examples of applications in which sine wave detection is used includes position detectors (U.S. Pat. No. 5,801,835), and speech recognition devices. In most applications, it is desirable to make the determination that the signal is a sinusoidal signal as quickly as possible. It is also desirable to do so in a manner that employs a relatively minimal amount of logic to implement the detection scheme.